The present invention relates to a multicomponent encoder suitable for making up a multiplex that may be referred to as a "X-PACKET" multiplex (where this term covers structures known under the names D2 MAC, DMAC, full time D2, full time D, and HD-MAC), each component comprising a sequence of packets and the packets being distributed in successive bursts each occupying a predetermined fraction of a TV frame line, said fraction lying anywhere in the range 0/1 to 1/1 and to a corresponding multicomponent decoder. The term "digital components" is used herein to designate all of the data from a source where the data is identified by a window in the frame: a sequence of bursts is an example of digital component.
A particularly important application of the invention lies in providing an encoder enabling a full time D2 or D type digital multiplex to be made up with the fraction of each component possibly extending up to the entire time allocated to active lines. An important complementary application lies in providing a decoder, particular a community decoder, enabling such a broadcast signal to be processed and distributed amongst subscriber lines.
Such a multiplex, and in particular a full time multiplex, must be adaptable to the needs of the broadcaster and to its program suppliers. Such needs may change. The number of sources to be broadcast may be increased, thereby increasing complexity. To make optimum use of resources, it is necessary that the time fractions allocated to different sources be easily changed.